Published: May 16, 2013 10:07 PM EDT
Updated: May 16, 2013 11:04 PM EDT

BOSTON, Mass.- The Boston bombings investigation has a new twist.  A law enforcement source confirmed suspect Dzhokhar Tsarnaev left a note claiming responsibility for the Boston Marathon bombings.  It was scribbled on a wall of the boat where he was hiding.  The message said the bombings were payback for attacks against muslims in Iraq and Afghanistan.  CBS correspondent and former assistant FBI Director John Miller says this new evidence may be the key for prosecutors.

He says regarding Tsarnaev "Once he was read Miranda, he stopped talking, so even if those statements are inadmissible, this miniature manifesto, written on the hull of this boat, serves as a backstop for his statements. They essentially parallel each other."

His brother, Tamerlan Tsarnaev died after a shootout with police.  The bombings killed three people and wounded more than two hundred others.